Monitoring ligand-receptor interactions is of paramount importance for the development of sensor platforms used in threat detection. To date, these devices have been bulky, insensitive, and/or difficult to use. For example, surface plasmon resonance (SPR) spectrometry requires an expensive, dedicated instrument and a trained operator. Moreover, the instrument is not easily portable and has only modest sensitivity. SPR also requires that the experiment be performed on a substrate with a thin gold film, which is used as the sensing element. Newer plasmonic assays, which are based on nanoparticles, can circumvent some of these difficulties, but often require amplification steps and are generally less sensitive than fluorescence-based detection, which is often capable of single molecule sensitivity. Moreover, fluorescence assays can be made compatible with portable, battery-operated, hand-held devices. Unfortunately, fluorescence measurements typically require that analytes of interest be labeled in order to make a measurement. This makes fluorescence strategies challenging and often impractical for many biosensor applications.
A need exist for simple, rapid, and effective methods and systems for detecting binding interactions. The present invention fulfills this need and provides further related advantages.